The son of a CIA analyst, Ames attended the University of Chicago for two years before becoming a CIA trainee in 1962; he also attended George Washington University (B.A., 1967). In 1969–72 Ames was posted to Ankara, Turkey, where he recruited U.S. spies from among Soviet nationals. He then lived in the United States until 1981, when he was posted to Mexico City, where he met his second wife, Maria del Rosario Casas Dupuy, a Colombian he recruited to work for the CIA. They married in 1985, while he was based again at CIA headquarters near Washington, D.C.; he was posted to Rome in 1986–89.

In 1985, aided by Rosario, who by then no longer worked for the CIA, Ames began selling American intelligence information to the KGB. At least 10 CIA agents within the Soviet Union were executed as a result of Ames’s spying; ultimately, he revealed the name of every U.S. agent operating in the Soviet Union (after 1991, Russia). Before Aldrich and Maria Ames were arrested in 1994, they had received more than $2.7 million, the most money paid by the Soviet Union or Russia to any American for spying. Ames was convicted of espionage and sentenced to life in prison, and his wife received a five-year sentence for tax evasion and conspiracy to commit espionage. Ames was imprisoned in the high-security United States Penitentiary in Allenwood, Pennsylvania. His story was the topic of the 1998 film Aldrich Ames: Traitor Within.